Kota Kinabalu: Sabah Parti Keadilan Rakyat (PKR) said an added mystery to the ongoing saga of the MH370 flight missing for 10 days while on a trip from Kuala Lumpur to Beijing is why none of the passengers aboard called or sent SMSes to people on the ground to alert them as to what was going on.

Referring to a Washington Post report, its Deputy Chairperson Christina Liew said more than 100 relatives had signed a statement saying they called their family members' mobile phones and heard the ringing tones but the calls were not answered.

She said while she was aware that it may be impossible to make calls or send SMSes using Malaysian handphones despite having roaming facilities at such heights like 40,000 ft due to lack of required frequency, there must surely be foreign nationals on board who may have had satellite phones.

"Even those using Malaysian handphones should have been able to get some quick messages through when the plane was travelling at below 5,000ft to avoid detection by radar as was reported while it was travelling across Kelantan after making a westerly turn near the Gulf of Thailand," she said.

Liew said a spokesperson from a telco that she spoke to who wished anonymity told her it was possible that someone with sophisticated knowledge used a phone jammer to disable all handphone communications.

"Could this explain why the phones were ringing but no one was answering?" she asked, adding this possibility should also be looked into.

The plane's transponder - which relays its location - was deliberately switched off two minutes after the co-pilot Fariq Abdul Hamid said the words "Alright, Goodnight" to ground controllers. A few minutes later the plane turned back on its flight path.

The planes ACARS system, which sends a signal every 30 minutes, was also manually turned off.

In the 911 hijacking, passengers in some of the planes that crashed into new Yorks Twin Towers were able to alert their relatives and friends.

The MAS flight carrying 239 people took off from the Kuala Lumpur International Airport at 12.41am on March 8 (Saturday) and was to have landed in Beijing at 6.30am the same day.

"Based on the revelation that the last known contact between the jetliner and satellites was at 8.11am, it meant that the aircraft was flying for more than seven hours after the takeoff. Its failure to land in Beijing surely would have prompted family members to make those phone calls.

"Phones were ringing and online accounts were active, yet no one was answering. Was there interference with the passengers' cellular phones?

"Could it also be possible that all their handphones were confiscated by someone on board the aircraft?" asked the Api-Api Assemblywoman.

"We must not omit any investigation options pertaining to the mysterious disappearance of the plane, no matter how remote the chances of success may be."

An experienced Sabahan pilot, when contacted by Daily Express, said the "ringing tones" indicate that the calls made were still within the Global System for Mobile Communications (GSM) network coverage.

The GSM is an international standard cellular service in which there is a commercial understanding between countries that any calls made would first be received by the host country's cellular communications provider before being connected to the subscribers.

"It is not known whether the Boeing 777-200 itself was also equipped with a satellite phone like in the Airbus.

What is puzzling is that no distress call whatsoever was also remitted by any of the crew or passengers," Liew noted.

Going by US satellite data, the jetliner climbed to 45,000 feet (above the approved limit for the Boeing 777-200) and then descended unevenly to 23,000 feet (below normal cruising levels) before dropping to an altitude of 5,000 feet (or even lower).

Liew said one could imagine the traumatic or horrifying experience of the crew and passengers.

"The first thing I would imagine they would do would have been to contact their beloved ones to tell them what was going on inside the aircraft or even capturing on handphone camera and emailing them.

"Our (Sabah PKR) thoughts are with the family members and we continue to pray for the safe return of all the passengers and crew," she said.